In recent years, a storage system provided with a plurality of storage devices is widely used to store a large volume of data treated in a computer system. As an example, there is a storage system that is provided with one or a plurality of storage media and a control device which controls data read and write on these storage media. For this control device, there is a known data control method in which data transmitted from a host device is stored in a buffer memory once and then the data is transferred from the buffer memory to a storage medium. This data control method requires a longer processing time to write data from the buffer memory to the storage medium than to receive and store the data from the host device to the buffer memory. To deal with this, there is a known technique of transmitting an interruption signal to the host device when the data transmission from the host device to the control device is completed so as to allow the host device to transmit next data. For example, please refer to Japanese Laid-Open Patent Publication No. 2000-20398.
The host device issues write commands, one type of which is a command to write a data block transmitted from the host device a specified number of times (WRITE SAME command). The control device that receives such a WRITE SAME command performs a process of writing the data block received from the host device, to a buffer memory one by one a specified number of times.
This data control method, however, has a drawback that it takes time to complete the writing because actual data is written to the buffer memory and this causes a delay in giving a response to the host device.